The purpose of this proposal is to extend our studies of the properties of the lens protein, beta-crystallin. This is the least well studied of the three major lens proteins, alpha, beta and gamma crystallin. Knowledge of the structure, evolution and sensitivity to specific noxious agents has direct relevance to cataract formation, susceptibility to cataract formation and the development of a rational approach to prevention. From present data there is reason to believe that a better understanding of the evolution of this protein with development and phylogenetically will engender information relevant to cataractogenesis.